Question

The oxidation number of $Mn$ in potassium permanganate is :

• A. $+6$
• B. $+7$
• C. $+5$
• D. $+8$

Answer 1

Answer: (B)

$+7$

Let $x$ be the oxidation number of manganese in potassium permanganate. ($KMn{O}_4$)

The oxidation numbers of potassium and oxygen are $+1$ and $-2$ respectively.

The sum of the oxidation numbers in a neutral molecule is zero.

Hence, $1+x+4(-2)=0$ or, $x=+7$.